The driver was combining XDP_TX virtqueue_kick and XDP_REDIRECT
map flushing (xdp_do_flush_map). This is suboptimal, these two
flush operations should be kept separate.
The suboptimal behavior was introduced in commit 9267c430c6b6
("virtio-net: add missing virtqueue kick when flushing packets").
Fixes: 9267c430c6b6 ("virtio-net: add missing virtqueue kick when flushing
packets")
Signed-off-by: Jesper Dangaard Brouer <bro...@redhat.com>
---
drivers/net/virtio_net.c | 30 +++++++++++++++++++-----------
1 file changed, 19 insertions(+), 11 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 1619ee3070b6..ae47ecf80c2d 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -53,6 +53,10 @@ module_param(napi_tx, bool, 0644);
/* Amount of XDP headroom to prepend to packets for use by xdp_adjust_head */
#define VIRTIO_XDP_HEADROOM 256
+/* Separating two types of XDP xmit */
+#define VIRTIO_XDP_TX BIT(0)
+#define VIRTIO_XDP_REDIR BIT(1)
+
/* RX packet size EWMA. The average packet size is used to determine the
packet
* buffer size when refilling RX rings. As the entire RX ring may be refilled
* at once, the weight is chosen so that the EWMA will be insensitive to
short-
@@ -582,7 +586,7 @@ static struct sk_buff *receive_small(struct net_device *dev,
struct receive_queue *rq,
void *buf, void *ctx,
unsigned int len,
- bool *xdp_xmit)
+ unsigned int *xdp_xmit)
{
struct sk_buff *skb;
struct bpf_prog *xdp_prog;
@@ -654,14 +658,14 @@ static struct sk_buff *receive_small(struct net_device
*dev,
trace_xdp_exception(vi->dev, xdp_prog, act);
goto err_xdp;
}
- *xdp_xmit = true;
+ *xdp_xmit |= VIRTIO_XDP_TX;
rcu_read_unlock();
goto xdp_xmit;
case XDP_REDIRECT:
err = xdp_do_redirect(dev, &xdp, xdp_prog);
if (err)
goto err_xdp;
- *xdp_xmit = true;
+ *xdp_xmit |= VIRTIO_XDP_REDIR;
rcu_read_unlock();
goto xdp_xmit;
default:
@@ -723,7 +727,7 @@ static struct sk_buff *receive_mergeable(struct net_device
*dev,
void *buf,
void *ctx,
unsigned int len,
- bool *xdp_xmit)
+ unsigned int *xdp_xmit)
{
struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
u16 num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);
@@ -818,7 +822,7 @@ static struct sk_buff *receive_mergeable(struct net_device
*dev,
put_page(xdp_page);
goto err_xdp;
}
- *xdp_xmit = true;
+ *xdp_xmit |= VIRTIO_XDP_TX;
if (unlikely(xdp_page != page))
put_page(page);
rcu_read_unlock();
@@ -830,7 +834,7 @@ static struct sk_buff *receive_mergeable(struct net_device
*dev,
put_page(xdp_page);
goto err_xdp;
}
- *xdp_xmit = true;
+ *xdp_xmit |= VIRTIO_XDP_REDIR;
if (unlikely(xdp_page != page))
put_page(page);
rcu_read_unlock();
@@ -939,7 +943,8 @@ static struct sk_buff *receive_mergeable(struct net_device
*dev,
}
static int receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
- void *buf, unsigned int len, void **ctx, bool *xdp_xmit)
+ void *buf, unsigned int len, void **ctx,
+ unsigned int *xdp_xmit)
{
struct net_device *dev = vi->dev;
struct sk_buff *skb;
@@ -1232,7 +1237,8 @@ static void refill_work(struct work_struct *work)
}
}
-static int virtnet_receive(struct receive_queue *rq, int budget, bool *xdp_xmit)
+static int virtnet_receive(struct receive_queue *rq, int budget,
+ unsigned int *xdp_xmit)
{
struct virtnet_info *vi = rq->vq->vdev->priv;
unsigned int len, received = 0, bytes = 0;
@@ -1321,7 +1327,7 @@ static int virtnet_poll(struct napi_struct *napi, int
budget)
struct virtnet_info *vi = rq->vq->vdev->priv;
struct send_queue *sq;
unsigned int received, qp;
- bool xdp_xmit = false;
+ unsigned int xdp_xmit = 0;
virtnet_poll_cleantx(rq);
@@ -1331,12 +1337,14 @@ static int virtnet_poll(struct napi_struct *napi, int budget)
if (received < budget)
virtqueue_napi_complete(napi, rq->vq, received);
- if (xdp_xmit) {
+ if (xdp_xmit & VIRTIO_XDP_REDIR)
+ xdp_do_flush_map();
+
+ if (xdp_xmit & VIRTIO_XDP_TX) {
qp = vi->curr_queue_pairs - vi->xdp_queue_pairs +
smp_processor_id();
sq = &vi->sq[qp];
virtqueue_kick(sq->vq);
- xdp_do_flush_map();
}
return received;
